The present invention relates generally to welding systems and, more particularly, to a stud welder having a post-firing stud connection detector system and control to inhibit subsequent firing of a welding stud gun if a recently fired welding stud is deemed connected to the stud welding gun.
Stud welding is a welding process that utilizes a localized burst of current between a metallic fastener and a metallic workpiece. In most instances, although not required, the fastener and the workpiece have the same material properties. The fasteners are held and welded in place through the use of an electro-mechanical device known as a stud gun. The stud gun typically has a chuck that holds the metallic fastener in place. A stud welding system generally has a power source, a stud gun, a pair of cables, and a stud.
Stud welding has applications in many industries. These industries include boiler manufacturing, shipbuilding, auto manufacturing, and construction to name but a few. The work environment in each of these trades is often polluted with dust, dirt, and debris and heavily congested with other equipment and tools. Any equipment operated under these conditions preferably should be designed with these conditions in mind in order to allow easy transport and to extend the life cycle of the equipment.
During welding a stud it is possible for the stud gun to not release the welding stud despite the stud having been welded to the workpiece. In such a situation, the chuck of the stud gun maintains at least partial retention of the welding stud. When this post-firing connection of the welding stud and stud welding gun occurs, it is not uncommon for an operator to re-trigger the stud welding gun while making attempts to dislodge the stud from the gun. Allowing this re-triggering has drawbacks.
Re-firing of the stud welding gun while attempting to release a stud already welded can cause damage to the stud welding gun as well as the welded stud. That is, with re-firing of the stud welding power source, it is possible to draw an arc between the stud welding gun and the welded stud as the operator draws or otherwise removes the stud welding gun from the head of the welded stud. As a result, a welding arc is formed between the stud welding gun and the welded stud. It is undesirable for both the gun and the stud to create an arc between the welded gun and the welded stud. Additionally, inadvertently drawing an arc between the welding stud gun and the welded stud can cause an unplanned arc flash.
Therefore, it would be desirable to have a system that detects connection of a welded stud to a stud welding gun. It would be further desirable to incorporate a control in a stud welder such that the stud welding gun cannot be fired if a welded stud remains connected to the stud welding gun.